Open AccessGene Expression Pattern after Insertion of Dexamethasone-Eluting Electrode into the Guinea Pig Cochlea
Author(s) -
Yutaka Takumi,
Shinya Nishio,
Kenneth G. Mugridge,
Tamio Oguchi,
Shingo Hashimoto,
N. Suzuki,
Satoshi Iwasaki,
Claude Jolly,
Shin Ichi Usami
Publication year - 2014
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0110238
Subject(s) - cochlea , dexamethasone , medicine , gene expression , cochlear implant , hearing loss , gene , biology , endocrinology , anatomy , audiology , biochemistry
A cochlear implant is an indispensable apparatus for a profound hearing loss patient. But insertion of the electrode entails a great deal of stress to the cochlea, and may cause irreversible damage to hair cells and related nerve structure. Although damage prevention effects of dexamethasone have been reported, long-term administration is difficult. In this study, we used a dexamethasone-eluting electrode in the guinea pig cochlea, and compared the gene expression after 7 days insertion with that of a normal electrode and non-surgically treated control by microarray. 40 genes were up-regulated 2-fold or more in the normal electrode group compared to the non-surgically treated group. Most of the up-regulated genes were associated with immune response and inflammation. In the dexamethasone-eluting group, compared to the normal electrode group, 7 of the 40 genes were further up-regulated, while 12 of them were down-regulated and there was a tendency to return to the non-surgical condition. 9 genes were down-regulated 2-fold or less with normal electrode insertion, and 4 of the 9 tended to return to the non-surgical condition in the dexamethasone-eluting group. These genes are certainly involved in the maintenance of the physiological functions of the cochlea. Our results indicate that the dexamethasone-eluting electrode will have an effect on the normalization of homeostasis in the cochlea.